Diesel vs Premium Diesel

I know I am labouring the point, but its important to get the cause and effect the right way around. It wasn't the higher RON petrol that improved the engine performance, it was because the engine was running on the lower RON petrol that resulted in reduced performance and worse fuel economy. The higher (correct) RON enabled the ECU to characterise the engine to perform as it was originally designed.
Not quite. The 1.9L Mi16 came in two versions, DFW (9.5:1) and D6C (10.4:1). The D6C was indeed designed to run on leaded 97 and didn't have a knock sensor at all. At the time, 98 didn't exist.
 
The Megane i rescued must have had 91 in it from previous owners... Its average urban consumption was through the roof and the idle a little rough. Mind you, the fuel being well over a year old probably didnt help...

But it ran just fine on it, the ecu pulling timing etc so there was no knocking. Ran it until the light came on and gave it some fresh 95 and there was not a massive change in performance but the fuel consumption came right back down!

Have tried 98 a few times in these, made zero difference. Same with the Giulietta with its very highly strung turbo 1.4, it is happy enough on 98 but no change in performance or economy from 95. So it just gets 95 from whatever servo happens to pop up after the light comes on...

I think the moral of this thread is - dont overthink it. Use what's recommended on the fuel door!
 
You had a Saab turbo? Man you need to try one of these suckers .... You'll love it!!

That was the model SAAB I had. It made 230bhp at the front wheels when I finished playing with it. Any more required a change to a larger turbocharger and then apparently the 5 speed box's strength becomes it's Achilles heel.

I've still got the supercharged 3 wheel Reliant to get some thrills in.💩🤣
 
DC was probably suggesting you try a CX Turbo - perhaps he'd let you have a drive of his!
 
DC was probably suggesting you try a CX Turbo - perhaps he'd let you have a drive of his!
Mmmmm, and he could have a drive of the Reliant, he'd love it.🤭
 
Mmmmm, and he could have a drive of the Reliant, he'd love it.🤭

There is crazies that fiddle with CX's too.....

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CGAT ... well known. Neil is a member here. Its currently running twin injectors and nitrous I think. I've never touched mine, you can only wind up the boost a small amount before the factory clutch will slip. The rest of the driveline is very robust though :) (unless your running lots of injectors and boost ... and nitrous :eek: ).

Mine would be down on power compared to most, I'm thinking hte old turbo on it needs a new core, its still goes extremely well, but I'm sure that 38 year old turbo isn't putting out the boost it once did :clown:

seeya,
Shane L.
 
Are you able to tell us roughly what advice you may or may not have given?

Roger
In that instance the "premium" fuel would be going to both the "truck" diesel pump in the truck area and the "premium" labelled pump in the car area. On the basis that they were delivering what they promised in the car area and a "better" fuel than promised in the truck area, I thought it was low risk.
 
In that instance the "premium" fuel would be going to both the "truck" diesel pump in the truck area and the "premium" labelled pump in the car area. On the basis that they were delivering what they promised in the car area and a "better" fuel than promised in the truck area, I thought it was low risk.
I have heard of 91 tanks at servos being filled with 95 if they were short on 91 that day.
 
I have heard of 91 tanks at servos being filled with 95 if they were short on 91 that day.
That is feasible but the stories about diluting the higher octane tanks with lower less costly fuels seems to be better based and make more sense as that would increase profit. o_O :eek: 91 seems to be the fuel that the industry quotes in media releases when 95 RON is probably the most used and recommended fuel for modern vehicles. Therefore more likely to be subject to subtle adjustment by profiteers.

98 seems to make a difference in smoother running of older vehicles that rebreath the vapours in the fuel tank (like our old trusty Fuego's) addition of aromatic additives may enhance that effect.

Observant owners will of course note all those factors in making their own choice of fuel.

Ken.
 
That is feasible but the stories about diluting the higher octane tanks with lower less costly fuels seems to be better based and make more sense as that would increase profit. o_O :eek: 91 seems to be the fuel that the industry quotes in media releases when 95 RON is probably the most used and recommended fuel for modern vehicles. Therefore more likely to be subject to subtle adjustment by profiteers.

98 seems to make a difference in smoother running of older vehicles that rebreath the vapours in the fuel tank (like our old trusty Fuego's) addition of aromatic additives may enhance that effect.

Observant owners will of course note all those factors in making their own choice of fuel.

Ken.
Carburettor cars are a different kettle of fish…
 
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